This is one of the most common mistakes fitness guru Bob Greene sees at his boot camps and the gym. To increase strength, you need to do your second and third sets of eight to ten reps with slightly fatigued muscles. If you have enough time to vent to your workout partner, then your muscles have enough time to recover. Instead of taking a break, Bob suggests, take a brief "pause" that lasts for just 15 to 30 seconds. "Any more than that and you'll lose the benefit you gained from the previous set," he says.
Read more: More workout mistakes